ZCZC SPCSWOMCD ALL ACUS11 KWNS 311247 SPC MCD 311247 ALZ000-MSZ000-LAZ000-311345- MESOSCALE DISCUSSION 0300 NWS STORM PREDICTION CENTER NORMAN OK 0747 AM CDT THU MAR 31 2016 AREAS AFFECTED...SOUTHERN MS AND SOUTHWEST AL CONCERNING...TORNADO WATCH 66... VALID 311247Z - 311345Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 66 CONTINUES. SUMMARY...AN ISOLATED TORNADO THREAT AND POTENTIAL FOR DAMAGING WINDS OR HAIL ARE CONFINED TO THE SOUTHEAST PORTION OF WW 66 FROM MARION AND PEARL RIVER COUNTIES TO FORREST COUNTY. THUNDERSTORMS WILL CONTINUE TO DEVELOP AND SPREAD ACROSS SOUTHEAST MS INTO SOUTHWEST AL THIS MORNING...THOUGH OVERALL SEVERE THREAT APPEARS LIMITED AT THIS TIME. NEW WATCH ISSUANCE IS UNLIKELY...THOUGH CONVECTIVE TRENDS WILL BE MONITORED. DISCUSSION...THE SOUTHERN EXTENT OF A COLD POOL ATTENDANT TO A LARGE AREA OF SHOWERS AND THUNDERSTORMS OVER MIDDLE TN TO SOUTHERN MS EXTENDED FROM CENTRAL AL TO WASHINGTON COUNTY AL TO WASHINGTON PARISH LA. A FEW STORMS IN VICINITY OF THIS BOUNDARY IN SOUTHEAST LA FROM 1030-12Z...FROM EAST FELICIANA PARISH TO WASHINGTON PARISH INDICATED STORM ROTATIONS PER TRENDS IN RADAR IMAGERY. THE DOWNSTREAM ENVIRONMENT HAS BEEN GRADUALLY MOISTENING/DESTABILIZING WITH SURFACE DEW POINTS NOW IN THE MIDDLE TO UPPER 60S ACROSS SOUTHEAST MS AND FAR SOUTHWEST AL...RESULTING IN MUCAPE OF 500-1000 J/KG. DESPITE MODEST INSTABILITY...THE PRESENCE OF STRONG DEEP-LAYER AND LOW-LEVEL SHEAR /EFFECTIVE SHEAR OF 45-50 KT AND EFFECTIVE SRH EXCEEDING 400 M2/S2 PER 12Z SLIDELL SOUNDING/ SUGGESTS AN ISOLATED TORNADO AND/OR DAMAGING WIND THREAT CANNOT BE RULED OUT WITH EASTWARD EXTENT. THE STRONGEST STORM PER SLIDELL AND JACKSON RADAR DATA WAS LOCATED OVER MARION AND LAMAR COUNTIES IN SOUTHEAST MS...WITH THIS ACTIVITY LOCATED NEAR...OR MORE LIKELY NORTH OF...THE AFOREMENTIONED BOUNDARY ATTENDANT TO THE LARGER COLD POOL. LOW-LEVEL WAA ACROSS THIS REGION SHOULD BE THE PRIMARY FORCING MECHANISM FOR NEW STORM DEVELOPMENT... AS LARGER SCALE FORCING FOR ASCENT SPREADS TO THE NORTHEAST AWAY FROM THE DISCUSSION AREA WITH A LEAD SHORTWAVE TROUGH. THIS WOULD SUGGEST THE TORNADO THREAT MAY TEND TO BE LESS THAN WHAT WAS OBSERVED EARLIER THIS MORNING ACROSS SOUTHEAST LA WITH THE ISSUANCE OF WW 66. ..PETERS/GOSS.. 03/31/2016 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MOB...JAN...LIX... LAT...LON 31098987 31348997 31719000 31818974 31818885 31888835 31868816 31788811 31488788 31198790 30958828 30878892 30818934 30818968 31098987 NNNN